how to change scale of BITMAPDATA

dear all

please help me to change the scale of map.i am using the fallowing code but it is not working.

var bitmapData:BitmapData=new BitmapData(map.width,map.height);
bitmapData.draw(map);
var scaleFactor:Number=2.5;
var newWidth:Number=bitmapData.width*scaleFactor;
var newHeight:Number=bitmapData.height*scaleFactor;
var scaledBitmapData:BitmapData=new BitmapData(newWidth,newHeight);
var scaleMatrix:Matrix=new Matrix();
scaleMatrix.scale(scaleFactor,scaleFactor);
scaledBitmapData.draw(bitmapData,scaleMatrix);
var byteArray:ByteArray =jpEncoder.encode(scaledBitmapData);

this code does not work.pleaSE help help robert shilten!---